Events

Lecture within WDS IPAS

Themal properties of crystals and amorphous solids. part 1 of 3 

prof. Oleksandr Kryvchikov

INTiBS PAN

Wykład jest otwarty. The lecture is open.

Outline:
1. General information about properties of  molecular matter with different structures.

• Some important experimental facts and physical ideas for the thermo physics of molecular solids.
• The concept of heat capacity. Dulong–Petit law. Experimental facts for simple and complex crystals, amorphous solids and disordered crystals.

2. Heat capacity of simple crystals.

• Crystals with complex structure. Optical phonons. Einstein's model. The law of dispersion. Heat capacity. Experimental data for simple molecular crystals.
• Heat capacity of amorphous solids and glassy-crystals. Low temperature anomalies. The boson maximum. The theoretical description. Comparative analysis between crystalline and amorphous solids. Low and ultra low thermal conductivity complex crystals.

3. Thermal conductivity  of simple crystals

• Thermal conductivity of molecular crystals. Phonon-phonon scattering processes. Eucken  law. Complex molecular crystals. Thermoelectric materials and other functional materials.
• Description of thermal conductivity in terms of quantum mechanics. Contribution of quasi-particles and quasi-waves to thermal conductivity. The effect of tunneling.

4. Thermal conductivity  of complex crystals and amorphous solids.

• Thermal conductivity of amorphous solids and its universal behavior. The influence of pressure, irradiation, porosity, etc. Glass-like behavior of the thermal conductivity of crystals of various types. Glassy crystals.
•  Theoretical description of the thermal conductivity of amorphous substances. A model of two level states. The model of soft potentials. Alain-Feldman model. Minimum thermal conductivity.

5. Thermal expansion of the molecular solids and nanostructures.